AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP6
The Structure and Assembly of Ordered Alkanethiol Monolayers on GaAs (001)

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: C.L. McGuiness, The Pennsylvania State University
Authors: C.L. McGuiness, The Pennsylvania State University
D. Blasini, Cornell University
S. Uppili, The Pennsylvania State University
A. Shaporenko, University of Heidelberg, Germany
M. Zharnikov, University of Heidelberg, Germany
D. Smilgies, CHESS
D. Allara, The Pennsylvania State University
Correspondent: Click to Email
We demonstrate through glancing angle x-ray diffraction (GIXRD), near edge x-ray adsorption fine structure (NEXAFS), infrared spectroscopy (IRS), x-ray photoelectron spectroscopy (XPS) and contact angle measurements that alkanethiol molecules will form densely packed, translationally ordered monolayers on GaAs(001) by solution adsorption. GIXRD data show that the adlayer molecules form a hcp structure which is incommensurate with the underlying square lattice of the substrate, an indication of extensive reconstruction arising during chemisorption. The combination of IRS and NEXAFS data determine an average molecular axis tilt of 13-15º with a high average degree of conformational ordering of the chains. This work gives the first definitive evidence for translationally ordered monolayers on GaAs. The ability to make highly structured and stable molecular films on GaAs will be critical in applications including molecular devices and electron beam resists.